To guarantee a linear guidance of the rails the two must be spaced from each other at least two points in their longitudinal direction. The distance between these two points becomes smaller the further the rails are withdrawn from one another, so that the stability of the telescopic rail suspension reduces the further a refrigerated goods carrier suspended on it is pulled out of the cooling chamber of the refrigerator. It is thus necessary to limit the movability of the rails so that the support points do not come too close to each other. The freedom of movement of the rails is thus generally significantly smaller than their length. Therefore it is also not possible, with a simple telescopic extension constructed from two rails, to make the freedom of movement of the refrigerated goods carrier large enough to enable it to be pulled out of the refrigerator compartment completely.
To achieve this objective, telescopic extensions with at least three rails able to be moved against each other are needed. These are far more expensive than those with two rails. It is thus not cost effective for a manufacturer wishing to offer a wide range of prices and equipment to use telescopic extensions with three rails throughout the range. If however both extensions with two rails and those with three or more rails are offered in the manufacturer's model range, the problem then arises of the different types of telescopic extensions requiring different amounts of space. Since the exterior dimensions of the refrigerators are predetermined in grid stages and there is also little variation in their wall thicknesses, account must be taken of the different space requirements of the different types of telescopic extension in the construction of the refrigerated goods carriers, i.e. for different models of refrigerators which differ in the type of extensions used, different refrigerated goods carriers will be needed. These must therefore be produced in a plurality of types in comparatively low volumes, which makes manufacturing more expensive.